Locking device for protecting door lock

ABSTRACT

A locking device includes a housing having a retaining hole for retaining a door lock, and a combination lock set. When the combination lock set is unlocked, a latch of the combination lock set is disengageable from a retaining portion of the housing such that a front shell of the housing is pivotable away from a rear shell of the housing, thereby opening an accommodation chamber defining between the front shell and the rear shell. As a result, the door lock is exposed outside for allowing a key to be inserted into a key hole thereof. When the combination lock set is locked, the latch is firmly engaged with the retaining portion such that the front shell is locked on the rear shell, causing the door lock to be hidden in the accommodation chamber.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to locks and more specifically, to a locking device that can be fastened to a door for protecting a door lock.

2. Description of the Related Art

Conventional locks generally include two types, i.e. a key controlled type, which needs a correct key to unlock it, and a combination controlled type, which needs a correct permutation of numbers or symbols to unlock it.

The key controlled lock is generally used on a front door of a house. When coming back home, a householder can insert a key into the lock, and then rotate it to open the front door. However, some people may inject super glue or instant glue into a keyhole of the lock impishly to clog the keyhole on purpose, such that the householder has to break the lock to open the front door and needs to change the broken lock to a new one, causing the householder great vexation. In addition, malicious people may inject quick-drying chemical glue into the keyhole to copy the key after the quick-drying chemical glue is turned into solid, such that these people can enter the house to steal valuables, resulting in huge loss for the family.

SUMMARY OF THE INVENTION

The present invention has been accomplished in view of the above-noted circumstances. It is therefore one objective of the present invention to provide a locking device, which can be fastened to a door for protecting a key hole of a door lock from being clogged by an unknown adhesive.

To achieve this objective of the present invention, the locking device comprises a housing and a combination lock set. The housing includes a front shell and a rear shell pivotally connected with the front shell to define an accommodation chamber therebetween and provided with a retaining portion and a retaining hole for retaining a door lock. The combination lock set is mounted to the front shell of the housing and received in the accommodation chamber and provided with a plurality of wheels, a movable plate controllable by the wheels to be moveable between a first position and a second position, and a latch engageable with the retaining portion of the rear shell.

When the wheels show a correct number permutation, the moveable plate is moved to the first position where the latch is disengageable from the retaining portion of the rear shell such that the front shell is pivotally moveable away from the rear shell, allowing the door lock to be exposed outside. When the wheels show a wrong number permutation, the moveable plate is moveable to the second position where the latch is blocked by the moveable plate and engageable with the retaining portion of the rear shell such that the front shell is locked on the rear shell, causing the door lock to be covered by the front shell.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a perspective view of a locking device according to a first preferred embodiment of the present invention;

FIG. 2 is an exploded view of the locking device according to the first preferred embodiment of the present invention;

FIG. 3 is a partially cutaway view of the locking device according to the first preferred embodiment of the present invention, showing that the combination lock set is locked;

FIG. 4 is a lateral cutaway view of the locking device according to the first preferred embodiment of the present invention, showing that the combination lock set is unlocked;

FIG. 5 is a front view of the locking device according to the first preferred embodiment of the present invention, showing that the locking device is fastened to a door and the front shell is pivotally moved away from the rear shell;

FIG. 6 is similar to FIG. 5, but showing the front shell is closed on the rear shell;

FIG. 7 is a partially exploded view of the locking device according to a second preferred embodiment of the present invention, and

FIG. 8 is a partially cutaway view of the locking device according to the second preferred embodiment of the present invention, showing the shackle is pulled upwards.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1 and 2, a locking device 10 in accordance with a first preferred embodiment of the present invention comprises a housing 20 and a combination lock set 30.

The housing 20 has a front shell 22 and a rear shell 24 pivotally connected with the front shell 22 so as to define an accommodation chamber 26 therebetween for accommodation of a memo, a note or small items. The front shell 22 has four openings 221 communicated between the accommodation chamber 26 and the outsides, and the rear shell 24 has a retaining hole 242 for retaining of a door lock 42, as shown in FIG. 5, a plurality of through holes 244 for penetration of screws 44 such that the rear shell 24 can be fastened to a door 40 through the screws 44, and a pair of retaining portions 246, each of which extends from the rear shell 24 toward the front shell 22 and has an insertion groove 248 at a distal end thereof. Further, the housing 20 includes a protecting cover 28 that is fitted to the rear side of the rear shell 24 through the insertion of protrusions 282 of the protecting cover 28 to insertion holes 25 of the rear shell 24 for preventing the rear shell 24 from contact with the door 40. To deserve to be mentioned, the way to fasten the housing 20 to the door 40 is embodied as, but not limited to, screw connections.

As shown in FIGS. 3 and 4, the combination lock set 30 is mounted to the front shell 22 to be received in the accommodation chamber 26 by means of a retaining base 32, and provided with a pair of latches 34, four combination wheels 36, and a movable plate 38. The latches 34 are slidably mounted in guide slots 322 of the retaining base 32 and stopped by a spring member 35 so as to be slidable relative the retaining base 32, and each have an insertion end 342 engagable with the insertion groove 248 of one of the retaining portions 246 of the rear shell 24. The combination wheels 36 are partially exposed to the outsides through the openings 221 of the front shell 22 for a user's operation. The movable plate 38 is connected with the combination wheels 36 to be pivotable relative to the latches 34 by the actuation of the combination wheels 36. When the combination lock set 30 is locked, the movable plate 38 is located between the latches 34 to block reciprocal movement of the latches 34 such that the insertion ends 342 of the latches 34 can be kept in engagement with the insertion grooves 248 of the rear shell 24, resulting in that the front shell 22 can not pivotally move away from the rear shell 24 so as to be firmly locked on the rear shell 24. When the combination lock set 30 is unlocked, the movable plate 38 is pivotally moved to be staggered with the latches 34 such that the insertion ends 342 of the latches 34 can be disengaged from the insertion grooves 248 of the rear shell 24 due to the movement of the latches 34, causing the front shell 22 to be pivotable relative to the rear shell 24.

By means of the aforesaid design, when a householder comes back home and rotates the combination wheels 36 to show the correct number permutation for unlocking the locking device 10, the movable plate 36 is pivotally moved to allow the latches 34 to be movable toward each other such that the householder can pull the front shell 22 away from the rear shell 24 to open the accommodation chamber 26 and expose the door lock 42, as shown in FIG. 5, and therefore the householder can insert a key into a keyhole 422 to unlock the door lock 42.

When leaving home, the householder can open the accommodation chamber 26 to lock the door lock 42, and then close the front shell 22 on the rear shell 24. Thereafter, the householder can rotate the combination wheels 36 to show a wrong number permutation respectively such that the movable plate 38 is stopped against the latches 34 to force the insertion ends 342 of the latches 34 to be engaged with the insertion grooves 248 of the rear shell 24. As a result, the door lock 42 can be hidden in the accommodation chamber 26 without exposure to the outsides, as shown in FIG. 6, thereby protecting the door lock 42 from getting clogged by an unknown adhesive and enhancing home safety.

FIG. 7 shows a locking device 50 in accordance with a second preferred embodiment of the present invention, further comprising a shackle 60, a retaining plate 70, and a switch 80.

The shackle 60 has a pivotal portion 62 and a hook portion 64 integrally connected with the pivotal portion 62. The pivotal portion 62 is pivotally connected with the rear shell 52, and axially moveable and pivotable relative to the rear shell 52. The hook portion 64 has a free end insertable into the rear shell 52 by means of the axial movement of the pivotal portion 62, and a recess 642 at the free end.

The retaining plate 70 is fastened to the rear shell 52, and provided with an elongated groove 72.

The switch 80 is movably mounted to the elongated groove 72 and stopped by a spring member 86, having a tab 82 and a retaining block 84 with a retaining end 842 that is engagable with the recess 642 of the hook portion 64 of the shackle 60.

It can be seen that the locking device 50 can be used as a conventional padlock. When wanting to unlock the shackle 60, a user can rotate the combination wheels 56 to open the accommodation chamber 54, and then move the switch 80 rightwards through the tab 82 to force the retaining end 842 of the retaining block 84 of the switch 80 to be disengaged from the recess 642 of the hook portion 64 of the shackle 60, as shown in FIG. 8. Accordingly, the user can pull the shackle 60 upwards to lock to-be-secured things.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

1. A locking device comprising: a housing having a front shell and a rear shell pivotally connected with the front shell to define an accommodation chamber therebetween and provided with a retaining portion and a retaining hole for retaining a door lock; and a combination lock set mounted to the front shell of the housing and received in the accommodation chamber, the combination lock set having a plurality of wheels, a latch engageable with the retaining portion of the rear shell, and a movable plate controlled by the wheels to be moveable between a first position where the latch is disengageable from the retaining portion of the rear shell such that the front shell is pivotally moveable away from the rear shell for allowing the door lock to be exposed outside when the wheels show a correct number permutation, and a second position where the latch is blocked by the moveable plate and engageable with the retaining portion of the rear shell such that the front shell is locked on the rear shell for enabling the door lock to be hidden in the accommodation chamber when the wheels show a wrong number permutation.
 2. The locking device as claimed in claim 1, wherein the latch of the combination lock set has an insertion end engagable with an insertion groove of the retaining portion of the rear shell of the housing.
 3. The locking device as claimed in claim 1, further comprising a shackle having a pivotal portion that is axially moveable and pivotable relative to the housing, and a hook portion that is integrally connected with the pivotal portion and provided with a free end insertable into the housing by means of an axial movement of the pivotal portion, and a recess at the free end, a retaining plate fastened to the rear shell of the housing, and a switch movably mounted to the retaining plate and provided with a retaining end engageable with the recess of the hook portion of the shackle.
 4. The locking device as claimed in claim 3, wherein the switch is movably mounted to an elongated groove of the retaining plate and provided with a tab and a retaining block with the retaining end.
 5. The locking device as claimed in claim 1, further comprising a protecting cover fitted to a rear side of the rear shell of the housing. 